Hello Martin
I don't know if the constructor of the following web site would know, if you emailed him direct? IX Engineer Command
http://www.ixengineercommand.com/airfields/general.php
He has a plan of Chateaudun
http://www.ixengineercommand.com/airfields/a39.php and I just wondered if he might have some info about your airfields of interest? Click on the plan to enlarge and it can be further enlarged by clicking the cursor +.
Regards Mark